Declicking The Clicks!
Declicking the clicks – it's pretty obvious what I'm going to discuss here! So first let me define what I'm talking about so we're clear. Clicks are extremely brief, random, sometimes loud spikes, in various ranges of frequencies that produce a ticking or popping sound. They're caused by things like a speck of dust lodged in a record groove, or even just a tiny microscopic crater within the groove itself; accidentally hitting a microphone; or an electrical switch being activated while recording, for example. As well, I'll briefly discuss click's sibling: crackles. Crackles are 'quieter', but no less annoying, clicks happening more predictably and steadily. They're the 'frying bacon' type sound often heard on old 78's or other badly worn vinyl. So let's start with clicks. What's the best approach for click removal? Manual or automated via software? That will depend on the number of clicks in the file. If there are say 10 clicks or less in a file, I prefer the manual approach. Beyond that I'll use software. Most times I'll use a combination: First I'll make a light pass with software, and then manually remove whatever's leftover. Light?? Remember, I mentioned that pushing declicking software too hard can create more clicks! This two step process I use simply cuts down on the time that would be required if click removal was done manually. Manual removal involves selecting the region where the click happens, and either redrawing the waveform to remove the click; or if you use WaveLab like I do, you can select from the restoration options provided. The shorter the click, the more likely successful you'll be. Longer areas will often involve re-generating surrounding regions to remove the click. This is very much a hit-or-miss solution. What if none these approaches work? My methods of last resort would either be to simply leave it - or - to delete the region where the click occurs. Now with spoken word files, the time shortening this approach involves won't drastically affect the delivery of the presentation 90 per cent of the time. But with music you must be more careful. There certainly will be a difference – after all, those minute timing variations are what give the best musicians their identifiable style and character to their playing. You need to listen closely to the region and also in a bigger perspective: 20 – 30 seconds before and after the affected area to hear whether the deletion adversely affects the performance. Of course, WaveLab has a superb time/pitch correction feature using the DIRAC processor. I would just restore the lost milliseconds in an area that'd be determined by where the deletion happened in the rhythm pattern. Declicking can be a very time consuming, sometimes frustrating, but ultimately rewarding process. Decrackling needs to be done with software. There's software by Waves, iZotope, and Algorithmix, to name just a few. WaveLab's Declicker plug-in does utilize a decrackling process when its 'Classic' option is engaged. I find it's the most successful when the clicks and crackles are 'above' the music in sound (noise?!) level. Algorithmix' decrackler is a superb program but it belongs at the start of the high-end (read: high-cost!) solutions. As always when dealing with any audio restoration or mastering software, my advice is always the same: Handle With Care!
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